## Elementary Technical Mathematics

$$7.46\times 10^{5}.$$
We multiply and divide the numbers as follows: $$\frac{84,000 \times 0.0004 \times 142,000}{0.002 \times 3200}\\ =\frac{(8.4\times 10^{4})(4\times 10^{-4})(1.42\times 10^{5})}{(2\times 10^{-3})(3.2\times 10^{3})} \\=\frac{4.771\times 10^{6}}{6.4\times 10^{0}} =7.46\times 10^{5}.$$